OVERALL OBJECTIVES OF THE PROJECT: 1) To determine the role of the capsule on N. gonorrhoeae in the pathogenesis of gonococcal disease. 2) To examine the feasibility of prevention or modification of gonococcal disease with a vaccine containing capsular antigen. GOALS FOR PROJECT PERIOD 7/1/78-6/30-79: 1) To determine whether the presumed capsular antigen does represent the gonococcal capsule. We plan to do this by determining whether antibody directed against the presumed capsular antigen will stain what is morphologically a capsule in the electron microscope. The sensitivity of the E.M. technique will be increased by the use of peroxidase-conjugated antibody against presumed capsular antigen. 2) To characterize the gonococcal capsule biochemically. In order to do this we will first purify capsular antigen in milligram quantities and then proceed to characterize it as detailed in the previous proposal. Capsular antigen may also be purified utilizing an affinity column with antibody directed against capsular antigen. 3) To determine the number of capsular serotypes of gonococci. Antibody directed against the capsular antigen will be produced by absorption of antisera against capsule with heterologous strains of gonococci. These monospecific antisera will then be used to determine capsular serotype with the fluorescent antibody technique. Antisera to strains of different capsular serotypes will be produced in rabbits with antigen purified by the same techniques utilized for purification of the capsular antigen from strain Cd.